The invention relates to a laundry treatment apparatus having a heat pump system in which process air for laundry treatment is dehumidified and heated.
In driers using a heat pump system for dehumidifying and heating the process air in a closed process air loop, excess energy has to be removed from the heat pump system as soon as the system has achieved a steady state of operation. The so called steady state is an optimum operation state in which the dehumidifying capacity of the evaporator and the heating capacity of the condenser are optimized in view of drying the laundry and energy consumption of the heat pump system. In the steady state the excess energy is the heat loss power introduced to the system by the compressor and which over the time would drive the system to an over-temperature and less-optimum operation, if not removed. From prior art different approaches are known to remove the excess energy when reaching the steady state.
A dryer having a heat pump system for dehumidifying and heating process air is known from WO 2008/086933 A. An auxiliary condenser cooled by ambient air is used to remove heat from the refrigerant loop in the heat pump system.
In the dryer of EP 2 034 084 A1 an auxiliary condenser of the heat pump system is arranged in the bottom section between an ambient air blower and a compressor such that the ambient air cools and removes excessive heat from both, the auxiliary condenser and the compressor.